The invention relates to a device for retrieving foam rubber, spherically shaped cleansing bodies which are circulated through the cooling system of a tubular heat exchanger or the like. The device has a sieve mounted inside a cylindrical housing, feed and discharge tubes, and valves for opening and closing the tubes.
It is conventional to clean the pipes of a water-cooled, tubular heat exchanger with spherically shaped cleansing bodies. They are made of foam rubber, or a similar material, have a diameter slightly larger than the inner diameter of the pipes, are pumped into the cooling water, and are subsequently forced through the pipes. After the cleansing bodies have passed the heat exchanger, they are retrieved from the cooling water by means of a filtration device and reintroduced into cooling water which flows toward the heat exchanger. Due to friction the cleansing bodies are subject to wear and abrasion. As their diameter decreases they must be removed from circulation and replaced.
Japanese Pat. No. 47 22765 accomplishes they by incorporating a sieve-like interceptor apparatus in the system. Such an interceptor has a filter sieve and a chamber directly beneath it. To each a discharge tube and associated valve mechanism are attached. The interceptor can be operated to allow the cooling water and the cleansing bodies entrained therein to circulate the bodies through the pipes during normal cleaning and to divert the bodies so that they are trapped by the sieve and retained in the interceptor. Trapped cleansing bodies in the sieve are removed and sorted, and those with excessively reduced diameters are replaced. In this arrangement the cleansing bodies are separated from the cooling water by carrying them in a flow of water through a pump, located upstream of the filter device, from the sieve past the interceptor and through one of the discharge tubes back into the cooling water pipes located upstream of the heat exchanger. This requires three valves which must be controlled and operated to open and close so that water can pass through, or cleansing bodies can be retrieved and inspected. Generally this requires complex, costly electronic controls and a corresponding number of actuating motors. Additionally, the typically used ball valves wear out quickly and thereby lose their seal.
Similar drawbacks are encountered with the retrieval device described in the German Pat. No. 32 27 708. It employs a conical sieve basket and a valve at the lower end thereof which alternately connects the outlet of the sieve basket, or a chamber located directly beneath it, with a discharge tube which, on the outside of the chamber, leads to a shut-off valve.